Illuminated instrument panel



oct. 14, 195s J. M. ROPR 2,855,710

ILLUMINATED INSTRUMENT PANEL Filed Sept. l1. 1956 2 'Sheets-Sheet l /f ff@ 9 STW @HM Cylu IDEM @HM ZZ l l l "T' ZZ /JZZ //W Z I y 7 f ,y W

7 z I ze y y INVENTOR JBHN F1. Roman m @Mw/50M ATTORNEYS Oct. 14, 1958 J. M. ROPER 2,855,710

ILLUMINATED INSTRUMENT PANEL Filed Sept. 11, 1956 2 Sheets-Sheet 2 J'oHN r1 Roper:

www@ MM www ATTORNEYS ILLUMINATED INSTRUMENT PANEL John M. Roper, Washington, D. C., assignor to Grimes Manufacturing Company, Urbana, Ohio, a corporation of Ohio Application September 11, 1956, Serial No. 609,239 8 Claims. (Cl. 40--130) This invention relates to panels which are illuminated so that the legends and indicia carried thereon may be read at night or under other circumstances involving the absence of adequate natural lighting.

More particularly, this invention has reference to the illumination of instrumentation panels by light transmitted through the medium of the material of which the panel is composed. This light is usually supplied by a source which is coupled closely to the panel and located substantially in the plane thereof. The rays of light are transmitted edgewise of the body of the panel and conlined therein except at the information areas defined by the legends or indicia. v

ln the usual practical installation of an illuminated panel of the foregoing type, the panel is fabricated from a plastic material which is transparent. The surfaces of the panel are processed with o-ne or more coatings of material which may, for example, include a white vinyl layer applied directly to the surfaces of the panel, and an overlying layer of opaque black vinyl. The black vinyl layer is appropriately etched or engraved so as to expose portions of the white vinyl layer in accordance with appropriate indicia or legends. The panel thus fabricated is processed with one or more holes which individually receive an associated lamp. These lamps when energized illuminate the interior of the panel, and inasmuch as the light is readily transmitted they also illuminate the legends which are rendered easily readable in contrast to their opaque black background.

Various arrangements have heretofore been proposed in the prior art for particular panel construction, including the application of various overlying layers of material for covering a transparent panel, and the positioning and support of lamp sockets and the energizing conductors for these sockets upon the panel. In View of the considerable advances made within recent years in the instrumentation for aircraft and other devicesrequiring a panel type disposition of controls, considerable demand now exists for commensurate improvements in the illuminated panel arrangements associated with such instrumentation.

United States Patent C Aircraft controls are becoming increasingly complex,

2,855,710 Patented Oct. 14, 1958 ice Moreover, because of the constant supervisory demands made upon present day aircraft pilots, -close attention is not given-in all instances to the operation of the control panel switches. These switches are quite frequently operated without directly viewing the control panel and on the basis of experience. The presencevof the projecting lamp sockets quite often result in the in advertent twisting of `socket caps in lieu of the proper switches or dials, thereby detracting from the pilots effective control over the aircraft.

Accordingly, a principal object of this inventionis to provide an improved lighting arrangement `for instrumentation control panels which is characterized by a complete absence of sockets or other lighting vequipment from the front surface of the panel, thereby improving the visibility of the controls and the readability of the infomation legends and, at the same time, substantially reducing the num-ber of components projecting from the front control panel surface which tend to complicate theappearance of the panel and confuse the operator.

Another object is to greatly simplify the construction of illuminated control panels so that they can be easily fabricated and installed.

Another object is to provide an illuminated control panel which will promote the more effective sealing of the chassis box or the like containing the electrical and'me* chanical components which are under control by the equipment operated lfrom the panel.

A preferred embodiment of this invention comprises a control panel made of easily workable transparent material such as plastic. A coating of white vinyl is applied to the edge and surface portions of the panel with an overlying layer of opaque black vinyl material covering at least the entire front panel surface which is exposed to the operator. Portions of the opaque layer on the front surface are removed in accordance with desired information areas such as legends and indicia which Vare to be illuminated and which are associated with switches and control knobs, etc. A plurality of lamp housings are appropriately positioned throughout the panel and within receiving holes formed in this panel so as not to project through the vinyl layers overlying the front panel surface. The panel is also processed with a plurality of through apertures for receiving the shafts of the controls -projecting from a chassis or the like mounted to the rear of the panel.

A preferred embodiment of each lamp housing includes a plastic cup for receiving a miniature lamp. The bottom and .side walls of this cup are inserted within a receiving hole in the panel with the bottom ilush with the panel surface portion carrying the information areas and wit-h the side walls projecting only from the rear panel sur face.

A tubular metallic sleeve is fixed within the cup so as to line a portion of the inner side walls removed from the bottom of the cup. A terminal lug electrically connected to this sleeve projects through the side walls of legends associated with the foregoing switches, dials and jacks in most instances have required vthat portions of the sockets for housing these components project from the front surface of 'the panel softhat ready access may be had to the enclosed lamps. It may be Areadily appreciated that these socket projections interfered with the readability of the panel instruments by increasing the number of components projecting from ythe front surface of the panel and presenting 'a highly complicated array to the operator. In many instances, the projecting lamp sockets obstructed ythe visibility of meter scales or the like.

the cup and is keyed to the plastic member by means of a receiving groove, and an electrical conductor is connected to this terminal lug whereby the appropriate electrical circuit can be established for interconnecting all of the illuminating lamps.

A lamp is positioned within the lamp housing so as to have a base contact contacting the metallic sleeve and an end contact exposed relative the side walls of the housing cup.

A metallic panel is coupled closely to the rear surface of `the plastic panel from which the lamp yhousing projects.

A tubular sleevel is fixed to and projects through the second panel away from the first panel. This sleeve receives the projecting portion of the lamp housing. A metallic cap is coupled to the projecting' portion of the latter sleeve so as to fully seal the lamp within the housing when the rst and second panels are positioned adjacent one another. A contact spring is fixed at the bottom of the nietallic cap so .as to establish contact with the lamp end contact. I

If desired, the cap structure mounted on the second or metallic panel may be soldered thereto so that this metallic panel may establish an effective moisture seal or cover for a component chassis mounted on the rear of this-panel.

AIn order that all of the features for attaining the objects of this invention may be readily understood, detailed reference is herein made to the accompanying drawings wherein: Y

vFigure 1 is an elevation view of an instrumentation control employing the panel of this invention,

Figure 2 is aplan view of the structure of Figure l and showing inrdetail the association of the first and second panels of this invention with respect to a chassis containing instrumentation components which are rack supported,

Figure 3 is a perspective view showing the front panel removed from the rear panel and otherwise in position for placement in operative association therewith,

FigureV 4 is a partial sectional view taken along line 4 4 of Figure 1 and showing the positioning of lamp socket with respect to the panels,

Figure 5 is a sectional view of the lamp housing shown in Figure 4, and

Figure 6 is a view showing the form of the receiving hole required for each lamp housing.

Referring now to Figures 1, 2 and 3 of the drawings, the preferred embodiment of the illuminated panel of this invention is shown in operative association with instrumentation or control apparatus which is confined within box-like chassis 10 (Figure 2). The components (not shown) located within box 10 are generally of an electrical and/or electronic nature 4and the circuitry thereof is manually controlled, for example, by a plurality of toggle switches 11 and a pointer knob 12 controlling a rotatable component such as a capacitor rotor.

The switches and knob are exposed for operation relative Van illuminated front panel 13 which contains information legends 14 which are `to be illuminated by lamps individually contained within each of sockets 1S (Figure 4). The actual contact mechanism of each switch 11 and the capacitor plates controlled by knob 12 are located within box 10, and a threaded shank of each component projects through the overlying panels for exposure at the face of illuminated panel 13." Box 10 is usually fabricated of material to provide some measure of shielding for the components disposed therein and also a common ground. In order to afford a completely effective shield and also a moisture and dust seal it is, of course, obvious that box 10 should be covered during the circuit operation by a metallic plate or thelike, and therefore a covering metallic panel or plate 16 is secured to the anges 17 formed integrally with the end walls of box 10 by means of screws 18. As will be hereinafter outlined in detail, metallic panel 16 also serves as a backing plate for illuminated panel 13 in such a manner as to appropriately support a portion of the sockets containing the illuminating lamps.

As is best shown in Figures 1 and 3, panel 13 is formed With a plurality of cutouts 19 and 19a, and panel 16 is formed with a plurality of. cutouts 20. It should be noted that cutouts 19a are substantially larger than the underlying cutouts 20 whereby the latter cutouts are exposed.

This arrangement of cutouts enables panels 13 and 16 to be mounted relative relay rack 21 so that panel 13 may be removed without disturbing backing panel 16. In particular, as is best shown in Figure 1, fasteners 22 are seated with respect to the cutouts 19 on panel 13 so as to secure panel 13 to the relay rack 21. Fasteners 23 are seated with respect to cutouts 20 on panel 16 where- 4 by this latter panel is individually secured to rack 21 in the event that the overlying panel 13`is removed.

The removal of panel 13 is effected simply by loosening the set screws for pointer knob 12 and removing this knob, withdrawing the retaining rings or nuts coupled to the threaded shafts of toggle switches 11, and removing fasteners 22. With these operations, panel 13 may be withdrawn from the backing metallic panel 16 as is best shown in Figure 3. It will be noted that there are no components projecting from the front surface of the removed panel 13 and that the smoothness of this surface is disturbed only by the apertures for receiving the switches 11 and knob 12. A portion of the sockets 15 for each of the illuminating lamps projects from the rear surface of panel 13 as will be hereinafter outlined in detail. In addition, a terminal prong (not shown) projects from the rear surface of panel 13. This prong establishes the necessary electrical connection to the illuminating lamps within sockets 15 whereby these lamps may be energized by an external filament supply source'which is connected to conductor 25 for panel socket 26 mounted on the rear surface of backing panel 16 (Figure 2).

The number and position of the various holes formed in panel 13 are determined by the particular elements which project from chassis 10 and which are to appear at the front surface of panel 13. The toggle switches and pointer knobs shown herein are .merely illustrative, land it should be understood that the principles of this invention are applicable to other arrangements of components on an illuminated panel.

Panel 13 is preferably fabricated of a transparent plastic member 24 whereby light energy introduced into the edges of the panel 'at the holes for receiving lamp housings 15 may be transmitted throughout the entire panel. In order vto prevent the undesired absorption of light introduced into the panel by means of the environmental structure, member 24 is preferably coated by a highly reflective white vinyl layer 27 as is best shown in the sectional view of Figure 4. Layer 27 is covered by an overlying layer 28 which is preferably of opaque Ablack vinyl. These coatings may be applied by any of the techniques which are now conventional in the art.

Legends 14 are formed by engraving or otherwise rcmoving the necessary portions of black vinyl 28 so as to expose in letter or numeral form the underlying white vinyl layer 27. The walls of the holes for receiving toggle switches 11 and the shaft controlled by pointer knob 12 are also preferably coated by both layers 27 and 28 in order to prevent the undesired escape of illumination at these areas.

The number and disposition of the sockets which are to illuminate the legends 14 are determined so as to adequately illuminate the legends and at the same time not interfere with the location of the operative components such as switches 11 and knob 12.

As is best shown in Figure 4, socket 15 comprises two principal subcombinations, namely, a lamp housing 30, and `a socket closure 31 for lamp housing 30 in the form of a removable end cap 32. Lamp housing 30 is supported by illuminated panel 13 and socket closure 31 is supported by metallic panel 16.

Lamp housing 30 in a preferred embodiment comi prises a translucent plastic cup 33 (Figure 5) which has a bottom 34 which forms a closure for cup side walls 35. It should be noted that the exterior surface of cup bottom 34 is flush with the front face of transparent mem- 'ber 24 (Figure 4) so that vinyl layers 27 and 28 are not interrupted in their smooth surface contours.

As is shown in the sectional view of Figure 5, an annular metallic sleeve 36 lines a portion of the walls of cup 33 remote from bottom 34. Terminal lug 37 is xedly connected to metallic sleeve 36 and projects through side wall 35 so as to provide an external electrical connection to 'a lamp 38 positioned within lamp housing 30. Terminal lug 37 is preferably keyed to d member 24V by means of a receiving groove 39 which is shown infFigure 6. An appropriate electrical conductor 40 is connected to terminal lug 37 whereby the `sockets may be electrically connected as desired. VConductor 40 may be applied to the rear surface of panel 13, or, in the alternative, it may be positioned in the interior of panel 13 by any of the techniques now well-known in regard to this art. 'The side walls 35 of lamp housing 30 project rearwardly from panel 13 in such ya manner that they may be received Within flanged sleeve 41 (Figure 4) fixedly supported on panel 16. Sleeve 41 projects from the rear surface of backing panel 16, and the projecting portions are threaded so that they may receive the mating threads of metallic socket cap 32. Ring 42 is preferably placed over the threaded projecting portion of sleeve 41 whereby a` moisture and dustproof seal may be effected by the cap 32 and sleeve 41.

A -contact 'spring 43 is fixed to the bottom of cap 32 so as to establish electrical contact with the end contact 44 of lamp 38. it should be noted that this end Contact projects slightly to the rear of the side walls of .lamp housing cup 33. The' glass envelope of lamp 38 is optically coupled to the interiorof panel 13 inasmuch as the inner side wall portion of cup 33 between the cup 'bottom 34 and sleeve36 is not lined. Accordingly, lamp 38 is energized by current flow in a circuit including conductor 40, lug 37, base contact 45 of lamp 38, the lament of lamp 38, end contact 44, contact spring 43, cap 32, sleeve 41 and metallic panel 16. inasmuch as the socket closures 31 for all of the sockets 15 are connected in multiple with respect to one another by means of metallic panel 16, all of the lamps within `the respective sockets 15 are connected in parallel. A series connection can be established by appropriately insulating the socket closures with respect to metallic panel 16 in the event that such a connection is desired. The parallel connection is advantageous, however, inasmuch as lament failure in one of the lamps will not seriously affect .the operation of the other lamps and in many instances suicient illumination can be obtained with this lamp condition so as to permit equipment operation until lamp replacement can be made.

l It should be noted that inasmuch as lamp sockets 15 do not project from the front panel surface of panel 13 obstructions Which would otherwise interfere with the movements of elements requiring considerable panel surface such as pointer 12 are eliminated. Outline 15a in Figure l, which represents the lamp for illuminating letters B, C, and D, in no way interferes with pointer 12. In the prior illumination arrangements, the yprojecting socket cap which is usually exposed with respect to an illuminating panel which corresponds to the present illuminated panel 13 would interfere with the present disposition of pointer 12 and, therefore, an optimum positioning of control components could probably not be attained scas to provide desired symmetry.

It is obvious, of course, that the panel arrangement of this invention simplifies the presentation of operational components inasmuch as no socket projections appear from the front surface of the operating panel, thereby minimizing confusion and reducing erroneous operation of the controls through inadvertency of a type which usually results in the twisting of the light sockets in lieu of the knob or the like. Additionally, the illuminating lamps may be easily checked and replaced if desired by simply removing pointer knob 12 and fasteners 22 and withdrawing panel 13 away from backing panel 16. Inasmuch as each of the lamps is held within their respective sockets by means of retaining spring 47 (Figure 5), the lamps are withdrawn from the companion socket closures 31. The lamps may be thereafter manually removed and checked, and replaced without the necessity for individually unscrewing socket end caps or the like.

The illuminating panel arrangement of this invention also promotes an improved moisture and dust seal 'for' the components housed within box 10. If desired, cap 32 may be soldered relative flange sleeve 41 and ring 42 whereby a very effective seal can be made at areas where the socket closures are xed to the backing panel 16. In the alternative, ring 42 can be omitted, and the space now occupied by the ring can be filled with solder. Accordingly, proper sealing of panel 16 with respect to box 10 and also the component shafts extending through panel 16 results in a highly efficient arrangement protecting against the harmful effects of dust with respect to the components housed within box 10.

It is to be understood that the above-described arrangements are illustrative of the application of the principles of this invention. Numerous other arrangements may be devised by those skilled in the art without departing from the scope of the invention.

Having thus described my invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Panel lighting apparatus comprisinga first panel including a member of light transmitting material, means to be illuminated fixed relative to said member and viewed from a front panel surface, a light conductive lamp housing positioned partially within a receiving hole in said panel flush with the front surface of said member and projecting past a rear surface of said panel, a second panel having a front surface mating closely with the rear surface of said panel with said two panels being generally parallel one another, and means including an end cap projecting from the surface of said second panel away from said first panel and receiving the projecting portion of said lamp housing.

2. Panellighting apparatus comprising a panel of light transmitting material, means to be illuminated fixed relative to said member and viewed from a front panel sur face, a lamp housing positioned partially within a receiving hole in said panel projecting only from the rear surface of said panel, a second panel having a front surface mating closely with the rear surface of said panel with said two panels being generally parallel one another, and closure means for said lamp housing projecting from the surface of said second panel away from said iirst panel and receiving the projecting portion of said lamp housing.

3. Panel lighting apparatus comprising a panel including a member'of light transmitting material, means to be illuminated iixed relative to said member and viewed from a front panel surface, a coating of light retiecting material covering the front surface of said member, a lamp housing positioned partially within a recess in said panel substantially flush with the front surface of said member in contact with said coating of light reiiecting material and projecting past a rear surface of said panel, a second body having a front surface mating closely with the rear surface of said lirst panel, and closure means supported on said body and receiving the projecting portion of said lamp housing. i

4. Panel lighting apparatus comprising a first panel including a member of light transmitting material, means to be illuminated fixed relative to said member and viewed from a front panel surface, a lamp housing including a light conducting cup having a bottom and side walls for receiving a lamp therein, said cup being positioned partially within a recess in said panel flush with the front surface of said member and the side walls projecting past a rear surface of said panel, a second panel having a front surface mating closely with the rear surface of said first panel, said two panels being generally parallel one another, and means including an end cap projecting from the rear surface of said second panel away from said first panel and receiving the projecting side wall portions of said lamp housing.

5. Panel lighting apparatus comprising a first panel including a member of light transmitting material, means to be illuminated fixed relative to said member and viewed from a front panel surface, a lamp housing including a light conducting cup having a bottom and sidewalls for receiving a lamp therein, said cup being positioned partially within a recess in said panel, the bottom of said recess being substantially flush with the front surface of said member and the side walls projecting past a rear surface of Said panel, a second panel having a front surface mating closely with the rear surfacevof said panel with said two panels being generally parallel one another, a sleeve positioned on said second panel and projecting from the rear surface of said second panel, said sleeve receiving the projecting side Wall portions of said lamp housing, and an end cap coupled to the projecting portion of said sleeve and closing said housing..

6. Panel lighting apparatus comprising a thin plastic member of transparent material, a layer of white vinyl material overlying a substantial surface portion of said member, a layer of opaque black vinyl material overlying a substantial surface portion of said white vinyl layer with portions of said opaque layer being removed in accordance with desired information areas which are to be illuminated, a lamp housing including a plastic cup having a bottom and side walls inserted within a receiving hole in said member, said bottom being flush with the surface of said member, said sidewalls projecting only from said member opposite the panel surface portion carrying said information areas, a tubular metallic sleeve xedly positioned Within and lining a portion of the inner side Walls of said cup removed from the bottom of said cup, a terminal lug electrically connected to said sleeve projecting through the side walls for said cup and keyed to said member by means of a receiving groove in said member, a metallic panel coupled closely to the surface of said plastic panel from which said lamp housing projects, and a metallic cap coupled to the projecting portion of saidv sleeve including a contact spring Xed to the bottom thereof.

7. Panel lighting apparatus comprising a thin panel including a member of transparent plastic material, a layer of light reflecting material overlying a substantial front surface portion of said member, `a layer of opaque material overlying a substantial surface portion of said light reecting layer with portions of said opaque layer being removedin accordance with desired information areas which are to be illuminated, a lamp housing including a plastic cup having a bottom and side walls inserted within a receiving hole in said panel with the bottom ush with the surface portion carrying said information areas and the side walls projecting only from the panel surface portion opposite the panel surface portion carrying said information areas, a tubular metallic sleeve xedly positioned within and lining .a portion of the inner side walls of said cup removed from the bottom of said cup, a terminal lug electrically connected to said sleeve projecting through vthe side walls for said `cup and keyedto a4 receiving groove in said member, a lamp positioned within said housing having a base contact contacting said metallic sleeve and an end contact exposed relative the projecting side walls of said cup, a second metallic panel coupled closely to the surface of said plastic panel from which said lamp housing projects, and a metallic cap coupled to the projecting portion of said sleeve including a contact spring fixed to the bottom thereof and contacting said lamp end contact.

8. Panel lighting apparatus Comprising a thin panel including a member of transparent plastic material, a layer of white vinyl material overlying a substantial surface portion of said member, a layer of opaque black vinyl material overlying a substantial surface portion of said white vinyl layer with portions lof said opaque layer being removed in accordance with desired information areas which are to be illuminated, Ia lamp housing including a plastic cup having a bottom and side Walls inserted within a recess in said member with the bottom ush with the surface portion carrying said information areas and the side walls projecting only from the member surface portion opposite the member surface portion carrying said information areas, a tubular metallic sleeve xedly positioned within and lining a portion of the inner side walls of said cup removed from the bottom of said cup, a terminal lug electrically connected to said sleeve projecting through the side walls for said cup and keyed to said member by means of a receiving groove in said member, a lamp positioned within said housing having a base contact contacting said metallic sleeve and `an end contact exposed relative the projecting side walls of said cup, a metallic panel coupled closely to the surface of said thin panel from which said lamp housing projects, and a metallic cap coupled to the projecting portion of said sleeve including a contact spring fixed to the bottom thereof and contacting said lamp end contact.

References Cited in the le of this patent UNITED STATES PATENTS 1,739,954 DuPont Dec. 17, 1929 2,518,726 Shelenker Aug. l5, 1950 2,637,802 Roper et al. May 5, 1953 2,660,824 Neugass Dec. 1, 1953 2,695,354 Neugass Nov. 23, 1954 FOREIGN PATENTS 895,017 France Mar. 27, 1944 

